Biomedical subjects

John St Cyr

Publications and source records attributed to John St Cyr.

6 recordsLinked to original sources

PubMed2006

Lack of oral embryotoxicity/teratogenicity with D-ribose in Wistar rats.

The present oral embryotoxicity/teratogenicity study of d-Ribose (DR) was conducted in female rats; 28 rats/group were exposed via the diet to 0, 5, 10, or 20% DR (0.0, 4.25, 7.94, 9.91g/kg body weight/day), from day 0 of gestation until Caesarian section and maternal sacrifice on day 21. All animals survived to the end of the study. Fecundity index, gestation index, pre-implantation loss, post-implantation loss, and sex ratio were all unaffected by treatment with DR. External observations of fetuses and placentas were unremarkable across the study groups. Mean fetal and placental weights, across all viable fetuses, did not differ significantly between treated and control groups. Observations of visceral malformations, anomalies, and variations were unremarkable and did not differ between treated and control groups. In summary, administration of DR to pregnant rats at concentrations up to 20% of the diet resulted in no significant adverse effects on the developing embryo/fetus at doses that were not otherwise a severe metabolic stress on the dam. A No Observed Adverse Effect Level (NOAEL) for teratogenicity could be seen at a concentration of 5% DR in the diet, corresponding to an average daily intake of DR of between 3.64 and 4.61g/kg body weight/day.

Animals↗

PubMed2006

Sub-chronic (13-week) oral toxicity study with D-ribose in Wistar rats.

The present study evaluated the toxicity from sub-chronic administration of D-ribose (DR) to male and female albino Wistar rats. Groups of 20 male and 20 female rats were exposed via the diet to 0%, 5%, 10%, or 20% DR, seven days per week (mean daily intake of 0.0, 3.6, 7.6, and 15.0 g/kg body weight/day in males and 0.0, 4.4, 8.5, and 15.7 g/kg body weight/day in females), for 13 consecutive weeks. Mean feed consumption and feed conversion efficiency values were comparable across all study groups; however, and mean body weights of all treated animals were decreased relative to those of controls. Absolute cecal weights were increased in the mid- and high-dose animals, and the relative weights were increased in all treated animals. Analysis of microscopic histopathology revealed no evidence of changes that could be attributed to the DR treatment. It is scientifically reasonable to conclude that the present study supports a concentration of 5% DR in the diet, corresponding to an average daily intake of DR of 3.6 and 4.4 g/kg body weight/day in male and female rats, respectively, as being the absolute no observed adverse effect level (NOAEL) for this substance.

Administration, Oral↗

PubMed2006

The use of D-ribose in chronic fatigue syndrome and fibromyalgia: a pilot study.

OBJECTIVES: Fibromyalgia (FMS) and chronic fatigue syndrome (CFS) are debilitating syndromes that are often associated with impaired cellular energy metabolism. As D-ribose has been shown to increase cellular energy synthesis in heart and skeletal muscle, this open-label uncontrolled pilot study was done to evaluate if D-ribose could improve symptoms in fibromyalgia and/or chronic fatigue syndrome patients. DESIGN: Forty-one (41) patients with a diagnosis of FMS and/or CFS were given D-ribose, a naturally occurring pentose carbohydrate, at a dose of 5 g t.i.d. for a total of 280 g. All patients completed questionnaires containing discrete visual analog scales and a global assessment pre- and post-D-ribose administration. RESULTS: D-ribose, which was well-tolerated, resulted in a significant improvement in all five visual analog scale (VAS) categories: energy; sleep; mental clarity; pain intensity; and well-being, as well as an improvement in patients' global assessment. Approximately 66% of patients experienced significant improvement while on D-ribose, with an average increase in energy on the VAS of 45% and an average improvement in overall well-being of 30% (p < 0.0001). CONCLUSIONS: D-ribose significantly reduced clinical symptoms in patients suffering from fibromyalgia and chronic fatigue syndrome.

Activities of Daily Living↗

PubMed2003

D-Ribose improves diastolic function and quality of life in congestive heart failure patients: a prospective feasibility study.

Patients with chronic coronary heart disease often suffer from congestive heart failure (CHF) despite multiple drug therapies. D-Ribose has been shown in animal models to improve cardiac energy metabolism and function following ischaemia. This was a prospective, double blind, randomized, crossover design study, to assess the effect of oral D-ribose supplementation on cardiac hemodynamics and quality of life in 15 patients with chronic coronary artery disease and CHF. The study consisted of two treatment periods of 3 weeks, during which either oral D-ribose or placebo was administered followed by a 1-week wash out period, and then administration of the other supplement. Assessment of myocardial functional parameters by echocardiography, quality of life using the SF-36 questionnaire and functional capacity using cycle ergometer testing was performed. The administration of D-ribose resulted in an enhancement of atrial contribution to left ventricular filling (40+/-11 vs. 45+/-9%, P=0.02), a smaller left atrial dimension (54+/-20 vs. 47+/-18 ml, P=0.02) and a shortened E wave deceleration (235+/-64 vs. 196+/-42, P=0.002) by echocardiography. Further, D-ribose also demonstrated a significant improvement of the patient's quality of life (417+/-118 vs. 467+/-128, P< or =0.01). In comparison, placebo did not result in any significant echocardiographic changes or in quality of life. This feasibility study in patients with coronary artery disease in CHF revealed the beneficial effects of D-ribose by improving diastolic functional parameters and enhancing quality of life.

Adenosine Triphosphate↗

PubMed2002

A new platelet preservative.

A new platelet preservative, ViaCyte trade mark (balanced salt solution, physiological buffer, D-ribose, bovine serum albumin, D-glucose, sterile water) was tested against the presently used storage solution (citrate-phosphate-dextrose; CPD) and results revealed that ViaCyte demonstrated added protection for platelets during storage-induced activation. Following five days of storage at room temperature, only 12.2% of platelets stored in ViaCyte exhibited P-selectin expression at rest and, upon thrombin challenge, 64.2% were activated, an increase of 42%. In control platelets (platelets stored in CDP), 44.4% were activated due to storage-induced lesions, and thrombin stimulation resulted in 47.9% P-selectin expression, an increase of only 2.5%. ViaCyte storage maintained the resting state and preserved platelet function, making more platelets available for activation upon agonist challenge. This preliminary study demonstrated that the presently used standard preservative does not offer protection from storage-induced lesions. Partially dysfunctional platelets do not contribute significantly to hemostasis in vivo and play little role, if any, in clot retraction and wound healing processes.

Blood Platelets↗

PubMed2002

Chronic, preclinical assessment of the Medtronic Advantage aortic valve prosthesis.

BACKGROUND AND AIMS OF THE STUDY: Medtronic, Inc. has designed and developed a new bileaflet, aortic prosthesis (Advantage) and, following an in-vitro analysis, a chronic in-vivo 20-week evaluation was performed in sheep. METHODS: Fourteen adult male and female sheep underwent implantation of either a 19 mm Advantage or St. Jude Medical (SJM) aortic prosthetic valve for chronic in-vivo evaluation, using a previously reported aortic model technique. RESULTS: There were two operative deaths, and the remaining sheep (eight with Advantage, four with SJM prostheses) underwent chronic hemodynamic and pathologic evaluations at approximately 140 days. One sheep (SJM prosthesis) died unexpectedly at 122 days; postmortem evaluation revealed valvular thrombosis, though the valve was well seated with no excessive pannus formation or paravalvular leaks. Hemodynamic and hematologic data in the remaining sheep were comparable. Pathologic examination of the remaining implanted valves revealed well-seated prostheses, with no evidence of thrombosis, no excessive pannus formation, and no evidence of paravalvular leaks. CONCLUSION: This preclinical animal study showed that the Advantage prosthesis has acceptable features, including equivalent hemodynamic and hematologic data, and a lack of pathological abnormalities when compared with a commercially available prosthetic bileaflet mechanical valve.

Animals↗